JP2009071541A - Image processor, image processing method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately correct colors according to color sense characteristics of a user so that even a user with color weakness to easily view input color image data. <P>SOLUTION: The user inputs the color sense characteristics by a color sense characteristics input part 2, while viewing a color patch displayed on an operation part. A color sense determining part 3 determines whether the user has color weakness or not, on the basis of the input color sense characteristics. A parameter generating part 4 generates a color correction parameter, on the basis of the input color sense characteristic. A color converting part 1 performs color correction by applying the color correction parameter to the input data, on the basis of information of the color sense determining part 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing method, a program, and a recording medium that perform color correction processing according to color vision characteristics on input color image data, and output the display. Scanner, digital camera, color printer, The present invention relates to a technique suitable for color correction devices such as color fax and color hard copy, software for color printers operating on personal computers and workstations, and the like.

  In recent years, with the development of color image output technology for displaying and printing color images, various colored characters and color images are used for documents and web pages created by individuals and companies. In such a document, in many cases, the color itself has important information by using colored characters or the like for notation for calling attention or grouping of graphs. In addition, in order to correctly understand the contents of these documents, it is necessary to recognize characters and images and to determine the difference in colors used in the documents.

  Even in a document using such various colors, it is difficult to distinguish color information when there is a defect in color vision. For example, in the case of color vision that is difficult to distinguish between red and green, it may be difficult to distinguish between red and green in a graph using red, green, and blue, or it may not be possible to distinguish at all. possible.

  By the way, according to the physiological and medical research on human color vision, the types of color blindness, such as red-green color blindness, yellow-blue color blindness, all-color blindness, etc. It is known that there is. Recently, CUDO (NPO Color Universal Design Organization) is not a line drawing that color vision is normal or abnormal, but C type / P type (strong / weak) (equivalent to conventional red-green blindness) / D type (strong / weak) ) (Equivalent to conventional red-green blindness) / T-type (equivalent to conventional yellow-blue blindness) / U-type (equivalent to conventional all-color blindness) It is proposed that a person who has a weak part in color recognition other than that is called a color weak person (see Non-Patent Document 1).

  Conventionally, in consideration of a user having such a color vision type, for example, in Patent Document 1, color vision such as the type and degree of color vision of a user is provided so that colors used in various documents can be easily identified. An image processing method has been proposed in which information about ambient brightness is input as characteristic information and user environment information, and adaptive conversion is performed on visual content accordingly.

  Further, in Patent Document 2, while the user looks at the hue circle displayed on the operation unit, the user specifies the color vision characteristic according to the distance for each color, determines the color vision characteristic of the user based on the information, and the color vision characteristic. There has been proposed an image processing apparatus that changes processing performed on image data in accordance with the above.

  Furthermore, in Patent Document 3, an outline is added at a color change in the image, or a pattern in a region having a certain pattern is changed in the image so that the image indicated by the drawing data is easy to see. There have been proposed printers that change the color in a certain pattern area, thicken the lines in the image, or change the color of the lines.

URI http: // www. cudo. jp / sikumi / Noboru Ota, "Color Engineering", Tokyo Denki University Press, pp. 209-211 JP 2005-524154 A JP 2004-94814 A JP 2001-293926 A

  In the case of the above-mentioned Patent Document 1, the user gives color vision type and degree information, and performs color correction according to the information, but the user does not always fully understand his / her color vision type and its degree. . In addition, since color vision characteristics generally vary from person to person, applying a uniform color vision type classification as described above may allow some users to identify without much color correction originally. In such a case, extra correction may be performed. Further, by performing such correction more than necessary, there is a high possibility that the color will become unnatural when viewed by a general color vision person.

  Further, in Patent Document 2, since the user can specify the color vision characteristic while looking at the hue circle displayed on the operation unit, the user can specify his own color vision type and degree as in Patent Document 1 and the like. Although there is a merit that it does not have to be grasped, a confusion color that is supposed to look the same color when the color direction characteristic is not considered and the color vision characteristic of the color weak is considered (Non-Patent Document 2) Can not be easily determined by causing a certain difference in the brightness direction without changing the color of the original image.

  Further, in Patent Document 3, as described above, in accordance with a user's instruction, an original image is processed in order to perform processing such as “add contour line at the change of image color” and “change color in a certain pattern area”. If a person with a color vision type different from that of the user sees the output, the image may have a very unnatural color or form.

The present invention has been made in view of the above problems,
An object of the present invention is to provide an image processing apparatus, an image processing method, a program, and a recording medium that perform appropriate color correction in accordance with the color vision characteristics of a user so that input color image data can be easily viewed by a color-weak person. There is.

  In other words, an object of the present invention is to provide an image processing apparatus that performs appropriate color correction in accordance with color vision characteristics relating to the color discrimination of the user so that the input color image data can be easily viewed even if the user is a color weak person. Is to provide.

  It is an object of the present invention to provide an image processing apparatus in which a user can input his own color vision characteristics regarding color discrimination with relative ease.

  An object of the present invention is to provide an image processing apparatus capable of performing color correction with high accuracy in accordance with color vision characteristics relating to color discrimination of a user.

  An object of the present invention is to provide an image processing apparatus capable of performing color correction for a weak color person who suppresses reversal of hue, saturation, and brightness.

  An object of the present invention is to provide an image processing apparatus capable of determining whether or not color correction for a weak color person is necessary from input color vision characteristic information relating to color discrimination.

  An object of the present invention is to provide an image processing method for performing appropriate color correction in accordance with color vision characteristics relating to a user's color discrimination so that the input color image data can be easily seen even if the user is a color weak person. There is to do.

  An object of the present invention is to provide an image processing program for performing appropriate color correction according to color vision characteristics relating to color discrimination of the user so that the input color image data is easy to see even if the user is a color weak person. There is to do.

  The present invention relates to an image processing apparatus for converting an input color image signal into an image signal for image formation of an image output apparatus, a color vision characteristic input means for inputting color vision characteristics relating to color discrimination at least in the brightness direction, and the color vision characteristics Parameter generation means for generating color correction parameters based on information input from the input means, color vision determination means for determining the presence or absence of color weakness based on information input from the color vision characteristic input means, and the color vision determination The main feature is that it comprises color correction means for performing color correction on the input color image signal using the color correction parameter when the means determines that the color is weak.

  Claims 1, 6, and 7: Since correction is performed using color correction parameters based on color vision characteristics relating to the user's color discrimination, even if the user is weak in color, it is necessary to respond to the degree of color weakness It is possible to perform color correction that enables color identification with minimal correction. In addition, by using the color vision characteristics relating to color discrimination in the brightness direction, it is possible to suppress the amount of correction of hue and saturation, and to perform color correction that is not so unnatural for general color blind persons.

  Claim 2: Since the user's color vision characteristics can be inputted while comparing the color of the color patch pairs, even if the user does not know his / her color vision type and degree, it is easy It is possible to input the color vision characteristics.

  Since the color vision characteristic can be input to the dividing points obtained by dividing the color space in the lightness, saturation, and hue directions, even if there are individual differences in the color vision characteristics of the user, it is highly accurate. It is possible to generate parameters for performing correct color correction.

  According to the fourth aspect of the present invention, the input of the color vision characteristics of the user is restricted, so that it is possible to suppress the generation of a parameter that reverses the positional relationship between hue and brightness.

  Claim 5: Since it is determined whether or not the user is weak in color from the input color vision characteristics, if the user is a general color blind person, no extra color correction is performed, and only if the user is a weak color person Appropriate color correction can be performed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1: (Color correction parameters are generated in accordance with color vision characteristics relating to color discrimination, and color correction for the weak is performed)
FIG. 1 shows the overall configuration of an image processing apparatus according to the present invention. The image processing apparatus shown in FIG. 1 includes a color conversion unit 1 that applies color correction parameters to input data based on information from the color vision determination unit 3, and a user operates an operation unit (not shown). A color vision characteristic input unit 2 for inputting color vision characteristics while looking at the color patches displayed on the screen, a color vision determination unit 3 for judging whether or not the user is weak in color from the inputted color vision characteristics, and based on the inputted color vision characteristics 2 has a parameter generation unit 4 for generating color correction parameters. Here, the color vision characteristic indicates information regarding a discrimination limit for identifying a color for each user.

  FIG. 2 shows a detailed configuration of the image processing apparatus according to the present invention. In FIG. 2, the color conversion unit 1 includes a confusion color determination unit 12 and a color correction unit 13.

  When the color vision characteristic input unit 2 receives color vision characteristic information regarding color discrimination that is input by the user while viewing a pair of color patches displayed on the operation unit (not shown), the color vision characteristic input unit 2 uses the color vision determination unit 3 and the parameter. The data is sent to the generation unit 4. The color vision determination unit 3 determines whether or not the user is a color weak person based on the received color vision characteristic information, and sends the determination result to the confusion color determination unit 12. When the parameter generation unit 4 receives the color vision characteristic information from the color vision characteristic input unit 2, the parameter generation unit 4 generates a color correction parameter based on the color vision characteristic information and sends the color correction parameter to the color correction unit 13.

  The confusion color determination unit 12 receives the determination information from the color vision determination unit 3, and when the user is weak in color, the color correction unit 13 together with the input data includes the confusion color information for determining the confusion color included in the input image. Send to. The color correction unit 13 applies the color correction parameter received from the parameter generation unit 4 to the input data based on the confusion color information received from the confusion color determination unit 12, performs color correction, and outputs the corrected data. To do.

  FIG. 3 is a process flowchart of the present invention. First, the color vision characteristic input unit 2 displays a user interface as shown in FIG. 4 on the operation unit, prompts the user to input color vision characteristic information, and the user inputs the color vision characteristic (step S11).

  While viewing the color patch pairs displayed as shown on the left side of FIG. 4, the user adjusts the slide bar corresponding to the hue, saturation, and brightness, and changes the color of one patch to change the left and right colors. The operation of making adjustments to such an extent that the patches are felt to be different is repeated as many times as the number of sets of color patch pairs.

  In the example of FIG. 4, the adjustment amounts ΔH, ΔS, ΔL when H = 60, S = 0.5, and L = 0.25 are sent to the parameter generation unit 4. The color patch pair to be displayed displays, for example, a color corresponding to a dividing point that equally divides the HSL color space.

  Since adjustment is performed for each point obtained by dividing the HSL color space, there is a possibility that the magnitude relationship of the hue angle may be reversed depending on the adjustment amount specified by the user. So, for example, when the user adjusts the hue and lightness in the positive direction and does not adjust the saturation at the time of adjusting a certain color patch pair, the target color patch pair to be adjusted thereafter As shown in FIG. 5, the input may be limited so that the hue and brightness can be adjusted only in the plus direction.

  The color vision characteristic information regarding the user's color discrimination input as described above is sent to the parameter generation unit 4 and the color vision determination unit 3. The color vision characteristic information corresponds to the adjustment amounts in the hue / saturation / lightness directions (referred to as ΔH, ΔS, and ΔL, respectively) for each color patch pair.

  When the parameter generation unit 4 receives the color vision characteristic information, the parameter generation unit 4 generates a color correction parameter as an adjustment amount table corresponding to each division point of the HSL color space as illustrated in FIG. 8A (step S12). That is, adjustment amounts (ΔH, ΔS, ΔL) corresponding to each color patch pair (H, L, S) are created as shown in FIG. 8A and are input to the color correction unit 13 as color correction parameters.

  At this time, for example, as shown in FIGS. 4 and 5, when the distance between the color patch pairs is long, a value such as ΔH input from the color vision characteristic input unit 2 may be used as it is. In addition, when rectangular color patch pairs are displayed in contact with each other and the user is prompted to input color vision characteristics, the color difference is perceived more than when the color patch pairs are displayed separately. Limits are low and even small differences may be perceived. However, in the input image, confusion colors that are difficult to distinguish between colors are not always in contact with each other. Therefore, if the color correction parameter is generated as it is, the correction amount by the color correction parameter is too small, and a sufficient effect may not be obtained. There is sex. Therefore, when displaying a color patch pair in contact with each other, ΔH obtained by multiplying the input adjustment amount by a constant as shown in the following equation (1) so that a sufficient difference is generated by correction by the color correction parameter. Codes such as those shown in FIG. 8B are used together with the color correction parameters that directly reflect the input adjustment amounts as shown in FIG. 8A, using ', ΔS', and ΔL 'as adjustment amounts. A color correction parameter for adjusting in the reverse direction is also generated.

ΔH '= ΔH * α
ΔS ′ = ΔS * α
ΔL ′ = ΔL * α (α is a constant larger than 1.0) (1)
The color correction parameters generated as described above are sent to the color correction unit 13. Upon receiving the color vision characteristic information, the color vision determination unit 3 determines whether the user is weak in color (step S13).

  First, a maximum value and an average value of absolute values of non-zero values (each of m1, m2, and m3) among the input adjustment amounts ΔH, ΔS, and ΔL for each color patch pair are calculated.

ΔHmean = (Σ | ΔH |) / m1
ΔSmean = (Σ | ΔS |) / m2
ΔLmean = (Σ | ΔL |) / m3
ΔHmax = max (| ΔH |)
ΔSmax = max (| ΔS |)
ΔLmax = max (| ΔL |) (2)
Where ΔLmean <Lth and ΔLmax <Lth
(However, Lth is a constant in the range of 0 <Lth <0.05 when the value of L in the HSL color space is 0 to 1) or other values such as ΔHmean are greater than or equal to a predetermined value The user is determined to be a color weak person.

ΔLmean ≧ Lth and ΔLmax ≧ Lth
(Lth is a constant in the range of 0 <Lth <0.05 when the value of L in the HSL color space is 0 to 1) or when other values such as ΔHmean are less than a predetermined value It is determined that the person is a general color vision person.

  The determination result as described above is sent to the confusion color determination unit 12. The confusion color determination unit 12 receives a determination result as to whether or not the user is weak in color from the color vision determination unit 3, and when it is determined that the user is weak in color, it is input via a network interface or various storage media. The color image data is converted into chromaticity and xyY chromaticity in the HSL color space, and a confusion color in the image is searched. Here, xyY is a value of CIE xy chromaticity and luminance Y.

  Here, for example, when the input data is sRGB data, the conversion to the HSL color space is performed by equation (3).

  As for the xyY chromaticity, sRGB data is converted into XYZ tristimulus values according to the definition formula of the sRGB color space, and then the xy chromaticity is calculated by the definition formula.

  Next, the confusion color determination unit 12 divides the input color image data for each color region used. For this, a well-known method can be used, for example, the method described in the chapter on region segmentation on page 689 or less of “Image Analysis Handbook” (published by the University of Tokyo Press) can be used. The detailed description about is omitted.

  Further, when the input data is data created by software such as a general office application, the input data is divided into regions according to the data structure such as lines, characters, and figures, and stored as region information.

  Next, based on the stored area information and the xyY color information obtained by converting the input color image data, color information that is determined to represent colors that are weakly confused with each other is retrieved, and the color information that is confused with each other. Is generated (step S14).

For the confusion color search processing method, for example, an average xyY chromaticity value is calculated for each held area, and for color information representing these areas, for example, Japanese Patent Application Laid-Open No. 2004-2467.
The method using the confusion line locus defined for each color vision characteristic shown in FIG. 6 as disclosed in Japanese Patent No. 39 can be applied, and detailed description thereof will be omitted. In addition, since the color vision determination unit 3 does not determine which color vision type the user is, the color confusion search is performed using the color vision type confusion lines shown in FIG. If the brightness Y representing each region is different by a predetermined value (for example, 5) or more, the confusion color is not searched (step S15).

  If a confusion color is found as a result of searching for the confusion color as described above, the color correction unit 13 performs color correction on an area other than the area with the largest number of pixels among the areas determined to be the confusion color. The confusion color information indicating the area is given and sent to the color correction unit 13 together with the HSL value of the input image data.

  When the color vision determination unit 3 determines that the user is a general color vision person, only the HSL value of the input image data is sent to the color correction unit 13.

  In the color correction unit 13, when the data received from the confusion color determination unit 12 includes confusion color information, the color correction parameters received from the parameter generation unit 4 for the pixels in the corresponding region (FIG. 8A). ) Is interpolated to calculate the adjustment amount and added to the HSL value of the input data. However, if there are two color correction parameters (FIGS. 8A and 8B) received from the parameter generation unit 4, the region shown in FIG. For areas where color confusion information is not applied using the color correction parameters, correction in the reverse direction is performed in the HSL color space using the other color correction parameters shown in FIG. 8B. As described above, the correction amount in the reverse direction is performed on the non-confused color area with respect to the area determined as the confused color, so that the color correction amount for the confused color can be relatively emphasized.

  After performing the color correction as described above, the color correction unit 13 sends the corrected HSL value to the confusion color determination unit 12. Then, the confusion color determination unit 12 converts the HSL value received from the color correction unit 13 into an RGB value using the equation (4), and again calculates an xyY value corresponding to the color-corrected HSL value.

  Then, the confusion color search process described above is performed again, the HSL value and the confusion color information are sent to the color correction unit 13, and the color correction unit 13 performs color correction using the color correction parameter. This determination of confusion color and color correction are repeated until there is no area determined to be a confusion color, or a predetermined number of times (for example, five times).

  When the data sent from the confusion color determination unit 12 does not include any confusion color information or when performing color correction a predetermined number of times, the color correction unit 13 uses the equation (4) to calculate the HSL value. Convert to RGB value and output.

  The data corrected in this way is sent to a color conversion unit (not shown) that converts RGB values into color signals for image formation, and the color correction unit applies the input data stored in advance. Conversion to image forming data is performed using a method such as interpolation using a 3D-LUT in which image forming data depending on the image forming apparatus is set.

  In the embodiment described above, even if the user with weak color does not fully grasp his / her color vision type, his / her color vision characteristics can be easily input, and based on the information, the color correction amount as small as possible Thus, it is possible to generate an image that is easy for the color weak to easily determine the color.

Example 2: (Example for media claim)
FIG. 7 shows a hardware configuration example of the image processing system according to the present invention. The computer 10 includes a program reading device 10a, a CPU 10b for controlling the whole, a RAM 10c used as a work area for the CPU 10b, a ROM 10d for storing a control program for the CPU 10b, a hard disk 10e, a NIC 10f, a mouse 10g, a keyboard 10h, an image It includes a display 11 on which data can be displayed and information can be input by a user touching the screen directly, and an image forming apparatus 12 such as a color printer. This image processing system can be realized by, for example, a workstation or a personal computer.

  In such a configuration, the CPU 10b can have the functions of the confusion color determination unit 12, the color correction unit 13, the color vision determination unit 3, and the parameter generation unit 4 shown in FIG. The function of the color vision characteristic input unit 2 can be provided in any of the mouse 10g, the keyboard 10h, and the display 11. Note that image processing functions such as color correction such as the CPU 10b can be provided, for example, in the form of a software package, specifically, an information recording medium such as a CD-ROM or a magnetic disk. In the example shown, when an information recording medium is set, a medium driving device for driving the information recording medium is provided (not shown).

  As described above, the image processing apparatus and the image processing method according to the present invention allow a general-purpose computer system having a display or the like to read a program recorded on an information recording medium such as a CD-ROM, and perform central processing of the general-purpose computer system. The present invention can also be implemented in an apparatus configuration in which the apparatus performs color correction based on color vision characteristic information input from an input interface. In this case, the program for executing the image processing of the present invention, that is, the program used in the hardware system is provided in a state recorded in a recording medium. The information recording medium on which the program or the like is recorded is not limited to a CD-ROM, and for example, a ROM, RAM, flash memory, magneto-optical disk, or the like may be used. The program recorded on the recording medium is installed in a storage device incorporated in the hardware system, for example, the hard disk 10e, so that this program can be executed to realize the color correction function.

  Further, the program for realizing the color correction function and the like of the present invention is not only provided in the form of a recording medium, but may be provided from a server through communication via a network, for example.

1 shows an overall configuration of an image processing apparatus according to the present invention. 1 shows a detailed configuration of an image processing apparatus according to the present invention. It is a processing flowchart of the present invention. The example of a color vision characteristic input screen is shown. The example of a color vision characteristic input screen when there is input restriction is shown. It is a figure explaining the confusion line in each color vision type. An example of the configuration when the present invention is implemented by software is shown. An example of color correction parameters is shown.

Explanation of symbols

1 color conversion unit 2 color vision characteristic input unit 3 color vision determination unit 4 parameter generation unit

Claims (8)

  In an image processing apparatus for converting an input color image signal into an image signal for image formation of an image output apparatus, color vision characteristic input means for inputting color vision characteristics regarding at least color discrimination in the brightness direction, and input from the color vision characteristic input means On the basis of the obtained information, a parameter generation unit that generates a color correction parameter, a color vision determination unit that determines presence / absence of color weakness based on the information input from the color vision characteristic input unit, and a color weakness determination by the color vision determination unit An image processing apparatus comprising: a color correction unit configured to perform color correction on the input color image signal using the color correction parameter when it is determined to be present.   The color vision characteristic input means displays color patch pairs in order on the operation unit screen, and inputs the color vision characteristics by adjusting the color patch pairs so that a user can discriminate each color patch pair. Item 6. The image processing apparatus according to Item 1.   The image processing apparatus according to claim 1, wherein the color patch pair is displayed in a plurality of stages at least in each of brightness, saturation, and hue direction.   The image processing apparatus according to claim 1, wherein the color vision characteristic input unit limits input performed by a user to the second and subsequent color patch pairs.   The image processing apparatus according to claim 1, wherein the color vision determination unit determines the presence or absence of color weakness based on information about a hue and brightness among information input from the color vision characteristic input unit.   In an image processing method for converting an input color image signal into an image signal for image formation of an image output device, a color vision characteristic input step for inputting color vision characteristics related to color discrimination at least in the brightness direction, and the color vision characteristic input step A parameter generation step for generating a color correction parameter based on the input information, a color vision determination step for determining the presence or absence of color weakness based on the information input from the color vision characteristic input step, and a determination in the color vision determination step And a color correction step of performing color correction on the input color image signal using the color correction parameter based on the result.   A program for causing a computer to realize the image processing method according to claim 6.   A computer-readable recording medium on which a program for causing a computer to implement the image processing method according to claim 6 is recorded.

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